Q24 of 61 Page 1

The position of three elements A, B and C in the Periodic Table are shown below:





















































Group



I



II



III



IV



V



VI



VII



Period










1



B









2









A



3








C




Giving reasons, explain the following:


(a) Element A is a non-metal.


(b) Atom of elements C has a larger size than atom of element A.


(c) Elements B has a valency of 1.

(a) Element A is lying in group VII and so, it will have 7 electrons in its outermost shell. A needs one more electron to obtain inert gas configuration and by gaining one electron it will form a monovalent negative ion. Therefore, A is a non-metal.


(b) Since C belongs to period 3 and has three shells while element A is in period 2 and will have only two shells therefore, element C will have large atomic size than element A.


(c) Since element B lies in group 1 and therefore it has 1 valence electron in its shell. It requires one more electron to get stable gas configuration. So its valency is 1.


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